Accepted answer

Few things here:

1.) Your main problem is that your LatLng puts you in the middle of Antarctica. If you reverse them you'll be near Bethesda, Maryland.

2.) You don't have an initialize function. I think you meant:

// Create the Google Map…\
function initialize() {
  var map = new google.maps.Map(document.getElementById("d3map"), {
    zoom: 12,
    center: new google.maps.LatLng(39.0087789,-77.1178769),
    mapTypeId: google.maps.MapTypeId.TERRAIN

3.) Probably not best practice to invent your own HTML tags:

<d3map ...

Should be:

<div id="d3map" ...

Here's an example fixing things up a bit.

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